Planting Techniques & Concepts
Assisting the process when natural regeneration is either unlikely or just too slow
Bird Corridors
Consider the project's role in the wider environment: if the bush is not large enough to sustain its own permanent populations, where are visiting birds coming from & passing to? Can fuel-stops be provided between known bird habitats to encourage these visits? Bird corridors between food sources are actually green stepping stones rather than a continous strip.
Defining Boundaries
Altering the existing shape of the bush, to improve edge-to-core ratio, can reduce 'edge effect' and enhance the viability of the core ecosystem. Long fingers of bush have a lower core ratio than the equivalent area in circular form, thus infilling between fragments is often more than just an aesthetic decision.
Sealing the Bush Edge
A healthy bush edge is gradual rather than abrupt, made up of low vegetation increasing in height over a short distance. Planting appropriate species around the bush edge to exclude light and reduce the wind's drying effect will reduce weed invasion and increase the number of plants naturally regenerating in this zone.
Eco-Sourcing
Unless the project area is highly modifed choose locally-sourced species to preserve the natural range of genetic variation particular to that region. Replicate natural regeneration by using seed-raised species rather than cutting-raised plants - therefore, no hybrids or cultivars. Eco-sourcing is best regarded as a pragmatic guideline rather than a religion, given the many wild-card factors which can prevent 'purity' being maintained.
Pioneer Planting
Use pioneer planting for open sites, extending bush edges and infilling broken canopies. Appropriate plants are usually quick-growing, often short-lived and, best of all, drought-hardy. Given the short-term nature of this style choose pragmatism over aesthetics, certainly when on a large scale, and plant out in a grid pattern - usually at a one-plant-per-square-metre density.
"Tui Tucker"
Native birds, such as tui, bellbirds & kereru, are natural pollinators and seed dispersers with an important role to play in regeneration projects. Supplying them with year-round food, by planting seasonal fruit and nectar sources, will encourage them to remain within the regenerating area. Planting non-natives should not be ruled out: for example, kereru devour the flowers & leaves of tree lucerne during the 'hungry gap' of late winter.
Self-Seeding Kanuka
"Establish kanuka in new areas by cutting then pegging down seed-laden branches onto bare soil. Make the layers 30-40 cm high then semi-cover with enough soil to provide 80-90% shade. Seedlings will soon germinate within the slash from the seeds it contains. This method makes kanuka very good for revegetating bare eroded surfaces. Like manuka, kanuka is an important pioneering or colonising native shrub because it prefers direct sunlight, so it provides good shelter for young native trees and acts as a nursery for them."
- Trees for Survival Trust -
Open-Ground Natives
Produce good-quality planting stock cheaply, by growing your own directly in the ground. Choose a nursery area onsite that provides the shelter & moisture most species need, planting up quick shelter species if the best site is exposed - good access is important too. Master the art of seed-raising; plant in rows, for efficiency; mulch to conserve moisture; remove all weeds, as they are great robbers of food and water. Root-wrenching is critical: some species respond better to this treatment than others.
Nursery-Cover Gorse
"For a revegetation project gorse should never be treated merely as a weed to be eradicated. The older the gorse the better: it is easier to cut into, suitable under-planting sites will abound and leaf litter will be thick. It is surprising how much the shade and shelter provided offsets the drier conditions. Between major canopy species it is advisable to plant quicker growing species, in advance of the decline of the shaded-out gorse cover, to help speed up initial canopy closure."
- Excerpt from 'Greening our Gulf Islands'
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